The experiment was conducted aiming at evaluating the levels of supplementation of vitamin D from two sources (vitamin D3 and 25-OHD3) on diets for broiler chickens raised in cages. It was used 1,500 line Cobb-700 male chicks at one day of age, housed in metal cages (100), with appliances and management fitted for bird raising. In each growing phase (starter, from 1 to 21 days; growing, from 22 to 38 days, and finishing, from 39 to 45 days), it was evaluated four levels (programs) of vitamin D supplementation (20/16/10; 37.5/30/18.8; 87.5/70/43.8 and 137.5/110/68.8 mg/kg ration) from two sources. The two additional treatments consisted of combination of the two sources (D3 + 25-OHD3) at different proportions (50+37.7/40+30/25+18.8 and 50+70/40+56/25+35 mg/kg ration for starter, growing and finishing phases, respectively). It was used a complete random experimental design, in a 2 × 4 + 2 (sources × levels + aditionals) and 10 replicates per treatment. The diets were based on corn and soybean meal, with supplementation of phytase (500 ftu/kg), following the recommendations of the national tables of nutritional requirements of non-ruminant animals. The performance and carcass characteristics as well as the intestinal morphology of the birds were evaluated. Vitamin-D supplementation at the starter phase improved weight gain and feed conversion of the birds. Greater weight gain and feed intake at 45 days of age were observed for the group of birds of the additional treatment associations. Carcass yield increased with the use of 25-OHD3. When compared to the single supplementation of vitamin D sources, the additional treatments promoted more benefits for most of the evaluated characteristics. The addition of 25-OHD3 in rations containing vitamin D3 improves performance characteristics of broilers.
metabolites of vitamin D3; vitamin D; vitamin D sources
